The invention relates to a screw spindle machine, e.g. a screw spindle pump or screw spindle compressor, having a tubular casing that is made of cast metal and is internally lined with a wear resistant layer, as well as a method of manufacturing such a screw spindle machine.
WO 2009/012837 A1 discloses a screw spindle pump having an internal cross-section in the shape of three overlapping circles. Thus, the interior of the casing forms three cylindrical chambers arranged side-by-side. The central chamber has a somewhat larger diameter than the two outer chambers and accommodates a main spindle, whereas each of the two outer chambers accommodates a side spindle that is in meshing and fluid-tight engagement with the main spindle. The internal surfaces of the chambers are lined with a wear resistant layer made of electrically conductive SiC, so that the wear caused by the main and the side spindles is reduced. In the manufacturing process, the internal surface of the SiC layer is shaped by means of electro-erosion and then polished by subsequent mechanical finishing, if necessary.